Add markdown renderer for motd (#1840)

* Add markdown renderer for motd

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

CHANGELOG.md

@@ -76,6 +76,7 @@ SPDX-License-Identifier: CC-BY-SA-4.0
 - Image tags with placeholder urls (`https://`) will be replaced with a placeholder frame.
 - Images that are currently uploading will be rendered as "uploading".
 - Code blocks with `plantuml` as language are rendered as [PlantUML](https://plantuml.com/) diagram using a configured render server.
+- File based motd that supports markdown without html.
 
 ### Changed
 

cypress/integration/motd.spec.ts

@@ -6,17 +6,18 @@
 
 const MOTD_LOCAL_STORAGE_KEY = 'motd.lastModified'
 const MOCK_LAST_MODIFIED = 'mockETag'
-const motdMockContent = 'This is the mock Motd call'
+const motdMockContent = 'This is the **mock** Motd call'
+const motdMockHtml = 'This is the <strong>mock</strong> Motd call'
 
 describe('Motd', () => {
-  const mockExistingMotd = (useEtag?: boolean) => {
+  const mockExistingMotd = (useEtag?: boolean, content = motdMockContent) => {
-    cy.intercept('GET', '/mock-backend/public/motd.txt', {
+    cy.intercept('GET', '/mock-backend/public/motd.md', {
       statusCode: 200,
       headers: { [useEtag ? 'etag' : 'Last-Modified']: MOCK_LAST_MODIFIED },
-      body: motdMockContent
+      body: content
     })
 
-    cy.intercept('HEAD', '/mock-backend/public/motd.txt', {
+    cy.intercept('HEAD', '/mock-backend/public/motd.md', {
       statusCode: 200,
       headers: { [useEtag ? 'etag' : 'Last-Modified']: MOCK_LAST_MODIFIED }
     })
@@ -29,13 +30,19 @@ describe('Motd', () => {
   it('shows the correct alert Motd text', () => {
     mockExistingMotd()
     cy.visitHome()
-    cy.getByCypressId('motd').contains(motdMockContent)
+    cy.getByCypressId('motd').find('.markdown-body').should('contain.html', motdMockHtml)
+  })
+
+  it("doesn't allow html in the motd", () => {
+    mockExistingMotd(false, '<iframe></iframe>')
+    cy.visitHome()
+    cy.getByCypressId('motd').find('.markdown-body').should('have.html', '<p>&lt;iframe&gt;&lt;/iframe&gt;</p>\n')
   })
 
   it('can be dismissed using etag', () => {
     mockExistingMotd(true)
     cy.visitHome()
-    cy.getByCypressId('motd').contains(motdMockContent)
+    cy.getByCypressId('motd').find('.markdown-body').should('contain.html', motdMockHtml)
     cy.getByCypressId('motd-dismiss')
       .click()
       .then(() => {
@@ -47,7 +54,7 @@ describe('Motd', () => {
   it('can be dismissed', () => {
     mockExistingMotd()
     cy.visitHome()
-    cy.getByCypressId('motd').contains(motdMockContent)
+    cy.getByCypressId('motd').find('.markdown-body').should('contain.html', motdMockHtml)
     cy.getByCypressId('motd-dismiss')
       .click()
       .then(() => {
@@ -59,7 +66,7 @@ describe('Motd', () => {
   it("won't show again after dismiss and reload", () => {
     mockExistingMotd()
     cy.visitHome()
-    cy.getByCypressId('motd').contains(motdMockContent)
+    cy.getByCypressId('motd').find('.markdown-body').should('contain.html', motdMockHtml)
     cy.getByCypressId('motd-dismiss')
       .click()
       .then(() => {
@@ -74,16 +81,16 @@ describe('Motd', () => {
   it('will show again after reload without dismiss', () => {
     mockExistingMotd()
     cy.visitHome()
-    cy.getByCypressId('motd').contains(motdMockContent)
+    cy.getByCypressId('motd').find('.markdown-body').should('contain.html', motdMockHtml)
     cy.reload()
     cy.get('main').should('exist')
-    cy.getByCypressId('motd').contains(motdMockContent)
+    cy.getByCypressId('motd').find('.markdown-body').should('contain.html', motdMockHtml)
   })
 
   it("won't show again after dismiss and page navigation", () => {
     mockExistingMotd()
     cy.visitHome()
-    cy.getByCypressId('motd').contains(motdMockContent)
+    cy.getByCypressId('motd').find('.markdown-body').should('contain.html', motdMockHtml)
     cy.getByCypressId('motd-dismiss')
       .click()
       .then(() => {

cypress/support/config.ts

@@ -68,11 +68,11 @@ Cypress.Commands.add('loadConfig', (additionalConfig?: Partial<typeof config>) =
 beforeEach(() => {
   cy.loadConfig()
 
-  cy.intercept('GET', '/mock-backend/public/motd.txt', {
+  cy.intercept('GET', '/mock-backend/public/motd.md', {
     body: '404 Not Found!',
     statusCode: 404
   })
-  cy.intercept('HEAD', '/mock-backend/public/motd.txt', {
+  cy.intercept('HEAD', '/mock-backend/public/motd.md', {
     statusCode: 404
   })
 })

netlify/intro.md

@@ -1,10 +1,4 @@
-<!--
+:::info
-SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
-
-SPDX-License-Identifier: CC-BY-SA-4.0
--->
-
-:::warning
 What you see is an UI-Test! It's filled with dummy data, not connected to a backend and no data will be saved.
 :::
 

netlify/motd.md

@@ -0,0 +1,6 @@
+This demo is hosted by [netlify](https://netlify.com).
+Please check their [privacy policy](https://netlify.com/privacy) as well as [our privacy policy](https://hedgedoc.org/privacy-policy).
+
+:::info
+What you see is an UI-Test! It's filled with dummy data, not connected to a backend and no data will be saved.
+:::

netlify/motd.md.license

@@ -0,0 +1,3 @@
+SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
+
+SPDX-License-Identifier: CC0-1.0

netlify/motd.txt

@@ -1,2 +0,0 @@
-This demo is hosted by netlify.
-Please check their privacy policy (https://netlify.com/privacy) as well as ours (https://hedgedoc.org/privacy-policy).

netlify/patch-files.sh

@@ -7,8 +7,8 @@ set -e
 
 echo 'Patch intro.md to include netlify banner.'
 cp netlify/intro.md public/mock-backend/public/intro.md
-echo 'Patch motd.txt to include privacy policy.'
+echo 'Patch motd.md to include privacy policy.'
-cp netlify/motd.txt public/mock-backend/public/motd.txt
+cp netlify/motd.md public/mock-backend/public/motd.md
 echo 'Patch version.json to include git hash'
 jq ".version = \"0.0.0+${GITHUB_SHA:0:8}\"" src/version.json > src/_version.json
 mv src/_version.json src/version.json

public/mock-backend/public/motd.md

@@ -1 +1,2 @@
 This is the test motd text
+:smile:

src/components/application-loader/initializers/fetch-motd.ts

@@ -17,12 +17,12 @@ const log = new Logger('Motd')
  * To check if the motd has changed the "last modified" header from the request
  * will be compared to the saved value from the browser's local storage.
  *
- * @param customizeAssetsUrl the URL where the motd.txt can be found.
+ * @param customizeAssetsUrl the URL where the motd.md can be found.
  * @return A promise that gets resolved if the motd was fetched successfully.
  */
 export const fetchMotd = async (customizeAssetsUrl: string): Promise<void> => {
   const cachedLastModified = window.localStorage.getItem(MOTD_LOCAL_STORAGE_KEY)
-  const motdUrl = `${customizeAssetsUrl}motd.txt`
+  const motdUrl = `${customizeAssetsUrl}motd.md`
 
   if (cachedLastModified) {
     const response = await fetch(motdUrl, {
@@ -48,7 +48,7 @@ export const fetchMotd = async (customizeAssetsUrl: string): Promise<void> => {
 
   const lastModified = response.headers.get('Last-Modified') || response.headers.get('etag')
   if (!lastModified) {
-    log.warn("'Last-Modified' or 'Etag' not found for motd.txt!")
+    log.warn("'Last-Modified' or 'Etag' not found for motd.md!")
   }
 
   const motdText = await response.text()

src/components/common/motd-modal/motd-modal.tsx

@@ -4,13 +4,16 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import React, { Fragment, useCallback, useMemo } from 'react'
+import React, { Suspense, useCallback } from 'react'
 import { Button, Modal } from 'react-bootstrap'
 import { CommonModal } from '../modals/common-modal'
 import { Trans, useTranslation } from 'react-i18next'
 import { useApplicationState } from '../../../hooks/common/use-application-state'
 import { dismissMotd } from '../../../redux/motd/methods'
 import { cypressId } from '../../../utils/cypress-attribute'
+import { WaitSpinner } from '../wait-spinner/wait-spinner'
+
+const MotdRenderer = React.lazy(() => import('./motd-renderer'))
 
 /**
  * Reads the motd from the global application state and shows it in a modal.
@@ -21,23 +24,6 @@ export const MotdModal: React.FC = () => {
   useTranslation()
   const motdState = useApplicationState((state) => state.motd)
 
-  const domContent = useMemo(() => {
-    if (!motdState) {
-      return null
-    }
-    let index = 0
-    return motdState.text
-      ?.split('\n')
-      .map((line) => <span key={(index += 1)}>{line}</span>)
-      .reduce((previousLine, currentLine, currentLineIndex) => (
-        <Fragment key={currentLineIndex}>
-          {previousLine}
-          <br />
-          {currentLine}
-        </Fragment>
-      ))
-  }, [motdState])
-
   const dismiss = useCallback(() => {
     if (!motdState) {
       return
@@ -49,8 +35,12 @@ export const MotdModal: React.FC = () => {
     return null
   } else {
     return (
-      <CommonModal {...cypressId('motd')} show={!!motdState} title={'motd.title'}>
+      <CommonModal {...cypressId('motd')} show={true} title={'motd.title'}>
-        <Modal.Body>{domContent}</Modal.Body>
+        <Modal.Body>
+          <Suspense fallback={<WaitSpinner />}>
+            <MotdRenderer />
+          </Suspense>
+        </Modal.Body>
         <Modal.Footer>
           <Button variant={'success'} onClick={dismiss} {...cypressId('motd-dismiss')}>
             <Trans i18nKey={'common.dismiss'} />

src/components/common/motd-modal/motd-renderer.tsx

@@ -0,0 +1,48 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import React, { useMemo } from 'react'
+import { GenericSyntaxMarkdownExtension } from '../../markdown-renderer/markdown-extension/generic-syntax-markdown-extension'
+import { useConvertMarkdownToReactDom } from '../../markdown-renderer/hooks/use-convert-markdown-to-react-dom'
+import { LinkifyFixMarkdownExtension } from '../../markdown-renderer/markdown-extension/linkify-fix-markdown-extension'
+import { EmojiMarkdownExtension } from '../../markdown-renderer/markdown-extension/emoji/emoji-markdown-extension'
+import { DebuggerMarkdownExtension } from '../../markdown-renderer/markdown-extension/debugger-markdown-extension'
+import { useApplicationState } from '../../../hooks/common/use-application-state'
+import { ProxyImageMarkdownExtension } from '../../markdown-renderer/markdown-extension/image/proxy-image-markdown-extension'
+import { YoutubeMarkdownExtension } from '../../markdown-renderer/markdown-extension/youtube/youtube-markdown-extension'
+import { AlertMarkdownExtension } from '../../markdown-renderer/markdown-extension/alert-markdown-extension'
+import { SpoilerMarkdownExtension } from '../../markdown-renderer/markdown-extension/spoiler-markdown-extension'
+import { BlockquoteExtraTagMarkdownExtension } from '../../markdown-renderer/markdown-extension/blockquote/blockquote-extra-tag-markdown-extension'
+import { VimeoMarkdownExtension } from '../../markdown-renderer/markdown-extension/vimeo/vimeo-markdown-extension'
+
+/**
+ * Reads the motd from the global application state and renders it as markdown with a subset of the usual features and without HTML support.
+ */
+export const MotdRenderer: React.FC = () => {
+  const extensions = useMemo(
+    () => [
+      new YoutubeMarkdownExtension(),
+      new VimeoMarkdownExtension(),
+      new ProxyImageMarkdownExtension(),
+      new BlockquoteExtraTagMarkdownExtension(),
+      new AlertMarkdownExtension(),
+      new SpoilerMarkdownExtension(),
+      new GenericSyntaxMarkdownExtension(),
+      new LinkifyFixMarkdownExtension(),
+      new EmojiMarkdownExtension(),
+      new DebuggerMarkdownExtension()
+    ],
+    []
+  )
+
+  const motdState = useApplicationState((state) => state.motd)
+  const lines = useMemo(() => (motdState ? motdState.text.split('\n') : []), [motdState])
+  const dom = useConvertMarkdownToReactDom(lines, extensions, true, false)
+
+  return <div className={'markdown-body'}>{dom}</div>
+}
+
+export default MotdRenderer

src/components/markdown-renderer/hooks/use-convert-markdown-to-react-dom.ts

@@ -21,12 +21,14 @@ import { SanitizerMarkdownExtension } from '../markdown-extension/sanitizer/sani
  * @param markdownContentLines The markdown code lines that should be rendered
  * @param additionalMarkdownExtensions A list of {@link MarkdownExtension markdown extensions} that should be used
  * @param newlinesAreBreaks Defines if the alternative break mode of markdown it should be used
+ * @param allowHtml Defines if html is allowed in markdown
  * @return The React DOM that represents the rendered markdown code
  */
 export const useConvertMarkdownToReactDom = (
   markdownContentLines: string[],
   additionalMarkdownExtensions: MarkdownExtension[],
-  newlinesAreBreaks?: boolean
+  newlinesAreBreaks = true,
+  allowHtml = true
 ): ValidReactDomElement[] => {
   const lineNumberMapper = useMemo(() => new LineIdMapper(), [])
   const htmlToReactTransformer = useMemo(() => new NodeToReactTransformer(), [])
@@ -40,8 +42,8 @@ export const useConvertMarkdownToReactDom = (
 
   const markdownIt = useMemo(() => {
     const newMarkdownIt = new MarkdownIt('default', {
-      html: true,
+      html: allowHtml,
-      breaks: newlinesAreBreaks ?? true,
+      breaks: newlinesAreBreaks,
       langPrefix: '',
       typographer: true
     })
@@ -52,7 +54,7 @@ export const useConvertMarkdownToReactDom = (
       newMarkdownIt.use((markdownIt) => extension.configureMarkdownItPost(markdownIt))
     )
     return newMarkdownIt
-  }, [markdownExtensions, newlinesAreBreaks])
+  }, [allowHtml, markdownExtensions, newlinesAreBreaks])
 
   useMemo(() => {
     const replacers = markdownExtensions.reduce(

src/components/markdown-renderer/replace-components/component-replacer.ts

@@ -6,7 +6,6 @@
 
 import type { Element, Node } from 'domhandler'
 import { isText } from 'domhandler'
-import type MarkdownIt from 'markdown-it'
 import type { ReactElement } from 'react'
 
 export type ValidReactDomElement = ReactElement | string | null
@@ -15,8 +14,6 @@ export type SubNodeTransform = (node: Node, subKey: number | string) => NodeRepl
 
 export type NativeRenderer = () => ValidReactDomElement
 
-export type MarkdownItPlugin = MarkdownIt.PluginSimple | MarkdownIt.PluginWithOptions | MarkdownIt.PluginWithParams
-
 export const REPLACE_WITH_NOTHING = null
 export const DO_NOT_REPLACE = undefined
 export type NodeReplacement = ValidReactDomElement | typeof REPLACE_WITH_NOTHING | typeof DO_NOT_REPLACE